This invention generally pertains to animal tethering devices and more particularly to improved means for anchoring such devices securely to the ground. The need for a tether exhibiting improved ground-holding characteristics is a long-standing one particularly in the cases of tethering large dogs or livestock or where the ground is sandy, wet or very friable.
Tethering stakes having a swiveled component to which an animal is attached by a chain or rope are well-known. Also known in the art of animal tethers are various ancillary structural assemblies which cooperate with the tether's main ground stake to provide added stability and enhanced ground-holding power.
U.S. Pat. No. 824,182 to Knoff teaches the use of an ancillary plate having curved prongs threadably attached to the upper shank portion of a central ground stake.
U.S. Pat. No. 2,812,743 to Dustin shows a central stake penetrating an ancillary plate having downturned ground engaging corners with apertures therethrough to receive discrete anchor pins which are driven angularly into the ground after the central stake is set.
U.S. Pat. No. 4,620,506 to Stubbs discloses an ancillary bed member having ground-penetrating legs and an aperture through which a central stake is driven. A collar affixed to the shank of the central stake coacts with a complementary recess in the bed to absorb lateral strain placed on the stake.
U.S. Pat. No. 4,491,091 to Satterfield exhibits an ancillary base plate having apertures for receiving a plurality of discrete stakes which are driven therethrough into the ground. A detachable swivel member is then assembled on an upstanding standard situated on the base plate.
A common structural feature of the aforedescribed tethering devices is a separate plate-like member to which are attached a plurality of ground-penetrating pins, blades, stakes or other such anchoring means in order to provide more ground-holding power than that provided by a single main stake. The prior art tethers suggested by Dustin and Satterfield require a plurality of discrete pins for securing the anchor plate to the ground; and, Stubbs requires that the legs of his bed be pounded into the ground before a central stake is likewise driven into the ground and assembled with the bed. Each of these devices require that their multiple parts be driven into the ground or assembled in several time consuming steps. With each of these multiple-part tethers there ia also a risk that component parts may be misplaced incidentally to moving from place to place.
The Knoff, Dustin and Stubbs tethers exhibit another structural drawback common to most devices intended for this purpose in that the main stake is not well suited to withstand the pounding required to drive it into the ground. All such prior art devices carry some sort of swivel structure at the impact receiving end of the stake; and, unless care is taken during impacting, the swivel components can be battered or broken thereby disabling the swivel. The Satterfield tether avoids this problem since it does not employ a main ground stake, but relies entirely on four discrete pins penetrating its platform to hold it in place.
It is also a common practice to utilize a conventional ball bearing assembly as a swivel component for animal tethers. U.S. Pat. No. 1,456,627 to Delbridge and U.S. Pat. No. 2,551,540 to Johnson show swivel plates rotatably mounted on tether stakes by means of antifriction bearing assemblies. The aforenoted Satterfield tether also utilizes a ball bearing swivel member. In none of these tethers is adequate provision made to protect the swivel's bearing components from misdirected impact blows; nor, is the bearing shielded from potentially damaging forces imparted to the swivel components as an incident to being inadvertently overrun by wheeled vehicles or being trod upon by a horse or other heavy animal attached to the tether. Moreover, the extensive aboveground projections of the Delbridge, Johnson, and Satterfield tethers are conducive to damage to the tether and damage or injury to any vehicle or animal which may accidentally impact the tether.
Another problem encountered in the use of typical prior art tethers having a single elongated ground stake is the difficulty in extracting the stake from the ground without bending the stake or damaging the swivel device customarily attached the top end of the stake. This problem is exacerbated in the case of the aforedescribed tethers having special means to provide extraordinary anchoring ability.